Moussavi was previously co-founder and co-principal of Foreign Office Architects (FOA) where she co-authored the design for the award-winning Yokohama International Ferry Terminal in Japan and was part of the United Architects team who were finalists for the Ground Zero competition, as well as the team that designed the London 2012 Olympics Masterplan. At FOA she completed a wide range of other international projects including the John Lewis Complex in Leicester, England; the South-East Coastal Park in Barcelona, Spain; and the Meydan Retail Complex in Istanbul, Turkey; and represented Britain at the 8th Venice Architecture Biennale in 2002.